TL 1 Thorax I WK 1 AY 24-25 STUDENT COPY PDF
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King Fahd University of Petroleum and Minerals
2024
Ali Alhakeem
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This document contains lecture notes on the thoracic wall, tracheobronchial tree, and thoracic cavity. It covers topics such as the functions, surface features, skeleton, apertures, and movements of the thorax. The document also includes information on the differences between the right and left lungs and specific anatomical features.
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Block 1.3 lectures 2024-2025 lecture Highlighter key Writer Reviewe...
Block 1.3 lectures 2024-2025 lecture Highlighter key Writer Reviewer Doctor explanation Abbreviation Key information Book >> >> Ali Alhakeem Abdulhameed Alabbadi Student explaintion 221-222-223 notes References Deleted Abdullah Alkhars Learning Objective 1.Thoracic wall (functions, surface features, skeleton, apertures, movements, muscles, fascia, vessels and nerves). 2.Tracheobronchial tree (larynx, trachea, bronchi with differences between right and left). 3.Thoracic cavity (pleura and lungs with Focus on the differences between the right and left lung). 1/22/2024 (C) KFU AY 24 -25 4 Respiration Structure of Respiratory System Theme Lecture 2 Dr. Naheed Kausar Assistant Professor Anatomy Division Biomedical Sciences Department College of Medicine 1/22/2024 (C) KFU AY 24 -25 3 “From The Reader” The thoracic cavity is divided into three major spaces: the central compartment or mediastinum that houses the thoracic viscera except for the lungs and, on each side, the right and left pulmonary cavities housing the lungs. The true thoracic wall includes the thoracic cage and the muscles that extend between the ribs as well as the skin, subcutaneous tissue, muscles, and fascia covering its anterolateral aspect. The domed shape of the thoracic cage provides remarkable rigidity, given the light weight of its components, enabling it to perform its functions (in the next slide). All the blue are from the reader and the doctor said it is important, the slides are not enough. Thoracic wall main functions More details in the next slide Functions: 1. Protection: Shields vital organs (heart, lungs, great vessels). 2. Respiration: Facilitates breathing by expanding and contracting during inhalation and exhalation. 3. Structural Support: Provides a rigid framework for attachment of muscles and tissues. 4. Movement: Allows flexibility for upper limb and neck movements, and aids in the movement of the rib cage during respiration. 1/22/2024 (C) KFU AY 24 -25 5 “From The Reader” 1. Protect vital thoracic and abdominal organs (most air or fluid filled) from external forces. 2. Resist the negative (sub-atmospheric) internal pressures generated by the elastic recoil of the lungs and inspiratory movements. 3. Provide attachment for and support the weight of the upper limbs. 4. Provide the anchoring attachment (origin) of many of the muscles that move and maintain the position of the upper limbs relative to the trunk, as well as provide the attachments for muscles of the abdomen, neck, back, and respiration. With each breath, the muscles of the thoracic wall—working in concert with the diaphragm and muscles of the abdominal wall—vary the volume of the thoracic cavity, first by expanding the capacity of the cavity, thereby causing the lungs to expand and draw air in and then, due to lung elasticity and muscle relaxation, decreasing the volume of the cavity and causing them to expel air. We cannot feel the first rib because it is covered by Surface Features the clavicle. Therefore, we begin counting from the second rib, using the sternal angle as a landmark. Clavicular Notch: Located on the manubrium, articulates with the clavicle. Sternal Angle (Angle of Louis): Junction between the manubrium and body of the sternum; an important landmark for locating rib 2. Clavicular Notch Costal Cartilages: Connect ribs to Manubrium the sternum. Sternal Angle Intercostal Spaces: Gaps between Body of the Sternum ribs filled with muscles and neurovascular structures. Xiphoid process 1/22/2024 (C) KFU AY 24 -25 6 Surface Features of Thoracic Wall These are imaginary lines that help us identify the contents of the thoracic cavity, such as the borders of the heart, lungs, pleura, and other structures. Anterior median line (AML) in midline anteriorly. Mid Clavicular line (MCL) passes through the midpoint of the The Clavicle clavicle, parallel to the AML. 1/22/2024 (C) KFU AY 24 -25 7 Surface Features of Thoracic Wall Posterior median (mid vertebral) line (PML) is a vertical line along the tips of the spinous processes of the vertebrae. Scapular line (SL) is Line through inferior angles of the scapula. 1/22/2024 (C) KFU AY 24 -25 7 Surface Features of Thoracic Wall Anterior axillary line (AAL) runs vertically along the anterior axillary fold Midaxillary line (MAL) runs from the apex (deepest part) of the axillary fossa Posterior axillary line (PAL) drawn vertically along the posterior axillary fold 1/22/2024 Skeleton The thoracic skeleton includes: Ribs: 12 pairs, each consisting of a bony part (vertebral end) and a cartilaginous part (sternal end). Sternum: Made up of the manubrium, body, and xiphoid process. Thoracic Vertebrae: 12 vertebrae (T1-T12), providing posterior attachment for the ribs. Sternum: Flat bone Ribs: Flat bones (The Dr. said they are irregular, but they are not) 12 Thoracic Vertebrae: Irregular bones 1/22/2024 (C) KFU AY 24 -25 9 The Thoracic Cage Formed by 12 thoracic vertebrae (posteriorly). 12 pairs of ribs and associated costal cartilages Sternum (anteriorly). 1/22/2024 (C) KFU AY 24 -25 10 “From The Reader” Based on the articulations, ribs can be classified into three major groups: True (vertebrocostal) ribs (1st-7th ribs): They attach directly to the sternum through their own costal cartilages. False (vertebrochondral) ribs (8th, 9th, and usually 10th ribs): Their cartilages are connected to the cartilage of the rib above them; thus their connection with the sternum is indirect. Floating (vertebral, free) ribs (11th, 12th, and sometimes 10th ribs): The rudimentary cartilages of these ribs do not connect even indirectly with the sternum; instead they end in the posterior abdominal musculature. Thoracic Apertures Superior Thoracic Aperture: structures like the trachea, esophagus, and major blood vessels pass Inferior Thoracic Aperture: bordered by the diaphragm. Aperture = Opening The superior thoracic aperture connects the thoracic cavity with the neck, while the inferior thoracic aperture connects the thoracic cavity with the abdominal cavity. 1/22/2024 (C) KFU AY 24 -25 11 “From The Reader” The thoracic cage is open superiorly and inferiorly: SUPERIOR THORACIC APERTURE The superior thoracic aperture is bounded: Posteriorly, by vertebra T1. Laterally, by the 1st pair of ribs and their costal cartilages. Anteriorly, by the superior border of the manubrium. Structures that pass between the thoracic cavity and the neck through the oblique, kidney- shaped superior thoracic aperture include the trachea, esophagus, nerves, and vessels that supply and drain the head, neck, and upper limbs. INFERIOR THORACIC APERTURE The inferior thoracic aperture, the anatomical thoracic outlet, is bounded as follows: Posteriorly, by the 12th thoracic vertebra. Posterolaterally, by the 11th and 12th pairs of ribs. Anterolaterally, by the joined costal cartilages of ribs 7-10, forming the costal margins. Anteriorly, by the xiphisternal joint. Sternum The Sternal angle corresponds to the vertebral column posteriorly at the level of Intervertebral disc between T4 & T5 vertebra. Importance: articulation of 2nd rib and landmark for internal structures like end of ascending aorta, beginning and end of arch of aorta, tracheal bifurcation. 1/22/2024 (C) KFU AY 24 -25 12 “From The Reader” The sternum consists of three parts: manubrium, body, and xiphoid process. The manubrium and body of the sternum lie in slightly different planes superior and inferior to their junction, the manubriosternal joint forms a projecting sternal angle (of Louis). xiphisternal joints: primary cartilaginous joint (synchondrosis) The manubriosternal joint is a secondary cartilaginous joint (symphysis) that allows slight movement, which helps in breathing. “Students explanation” Sternal Angle (Angle of Louis): Key Landmarks 2 Bones 2 Beginnings 2 Terminations 2 Bifurcations Bifurcation of Second rib Beginning of the Termination of the the trachea into (articulates here). aortic arch. aortic arch. right and left main bronchi. Termination of the Intervertebral disc Beginning of the arch of the azygos Bifurcation of between T4 and descending vein into the the pulmonary T5 vertebrae. thoracic aorta. superior vena trunk. cava (SVC). Thoracic vertebrae Number: Total 12 (T1 – T12) Body: Heart shaped Vertebral foramen: Circular and smaller. Transverse processes: Long and strong, have facets. Articular processes: Superior posteriorly and laterally; inferior facets anteriorly and medially; Spinous processes: Long; sloping downwards. 1/22/2024 (C) KFU AY 24 -25 13 The cardinal difference The transverse costal facets are the points on the thoracic vertebrae between the thoracic and lumbar vertebrae is that the where the tubercles of the ribs articulate with the vertebrae. thoracic vertebrae have The articular processes of vertebrae form joints between adjacent vertebrae. The superior costal facets to articulate with the ribs, whereas the articular facets face posteriorly and laterally, while the inferior articular facets face lumbar vertebrae do not. anteriorly and medially Ribs 1/22/2024 (C) KFU AY 24 -25 14 We can classify the ribs based on their articulations with the sternum (as mentioned previously) and their features into typical and atypical ribs. Typical Ribs: (3rd to 9th) Features: Head, neck, tubercle, Body (shaft including angle) Costal cartilage Remember that the costal groove is located near the inferior border of the rib on the inner surface. Three structures pass through and are protected by the costal groove, collectively referred to as VAN: 1. Vein بالترتيب من فوق لتحت 2. Artery 3. Nerve “From The Reader” Atypical Ribs: (1st, 2nd, 10th - 12th ribs): The 1st rib is widest, nearly horizontal, shortest, and most sharply curved. The 2nd rib has a rough area on its upper surface for serratus anterior. The 10th-12th ribs have only one facet on their heads and articulate with a single vertebra. The 11th and 12th ribs are short and have no neck or tubercle. Joints of thorax Joints between ribs and sternum joint between ribs & vertebrae. ▪ First sternocostal joint : Primary cartilaginous joint ▪ 2nd to 7th sternocostal joint: Plane synovial ▪ Manubriosternal joint: Secondary cartilaginous or Symphysial joint. 1/22/2024 (C) KFU AY 24 -25 15 The first sternocostal joint is a The 2nd to 7th sternocostal joints are primary cartilaginous joint plane synovial joints located between between the first rib and the the sternum and the costal cartilages. manubrium. This joint shows These joints have a small synovial cavity no movement, so the rib and and allow slight movements, which assist the manubrium move as a in inhalation and exhalation single unit. (respiration). The manubriosternal joint is a secondary cartilaginous joint (symphysis) that allows slight movement, which aids in breathing. All of the costochondral joints are primary cartilaginous joints located between the ribs and their corresponding costal cartilage. The head of the rib articulates with two Remember that the head of the rib vertebrae: the corresponding vertebra (below) articulates with the vertebra (posteriorly), and the vertebra above it. The rib's number while the anterior end (via the costal corresponds to the lower vertebra it articulates cartilage) articulates with the sternum. with. “From The Reader” COSTOVERTEBRAL JOINTS: Plane synovial joint between ribs & vertebrae ( two joints) The joints of heads of ribs Costotransverse Joints The heads of the ribs connect closely The costotransverse joints are formed to the vertebral bodies, allowing only between the tubercles of the ribs and slight gliding movements at the the transverse processes of the (demi)facets. These small movements corresponding vertebrae. can produce a relatively large (The movements will be explained in excursion of the distal (sternal or the next slide.) anterior) end of the rib. “From The Reader” Costotransverse Joint Movements Superior 6 Ribs 7th to 10th Ribs The articular surfaces on the The articular surfaces of the tubercles tubercles of the superior 6 ribs are and transverse processes are flat, convex and fit into concavities allowing for gliding movements on the transverse processes. rather than rotation. This structure allows for rotation This results in elevation and around a mostly transverse axis depression of the lateral-most portions passing through the head, neck of of these ribs in the transverse plane the rib, and intra-articular (bucket-handle movement). ligament. This results in elevation and depression movements of the sternal ends of the ribs and the sternum in the sagittal plane (pump- handle movement). Respiratory Movements o Elevation/Depression: Ribs move up and out (inhalation), and down and in (exhalation). o Bucket Handle Motion: Lateral movement of the ribs, expanding the chest laterally. o Pump Handle Motion: Anterior and superior movement of the sternum during inhalation, increasing the volume of the thoracic cavity. 1/22/2024 (C) KFU AY 24 -25 16 These are the movements of inhalation and exhalation that cause elevation and depression of the diaphragm. 1/22/2024 (C) KFU AY 24 -25 17 Breathing Movements 1/22/2024 (C) KFU AY 24 -25 18 1/22/2024 (C) KFU AY 24 -25 19 Breathing Movements 1/22/2024 (C) KFU AY 24 -25 20 Breathing Movements Pump Handle movement: Increase in Anteroposterior dimension Bucket Handle movement: Increase in transverse dimension 1/22/2024 (C) KFU AY 24 -25 21 Breathing Movements Contraction of diaphragm during inspiration increases Vertical Diameter and reverse during expiration 1/22/2024 (C) KFU AY 24 -25 22 Muscles The intercostal muscles are located between each pair of ribs, occupying the intercostal spaces. External Intercostals: Elevate the ribs during inspiration. Internal Intercostals: Depress the ribs during forced expiration. Innermost Intercostals: Assist with respiration. The diaphragm Diaphragm: Primary muscle for inspiration, separates is considered the principal the thoracic and abdominal cavities. muscle of respiration. Accessory Muscles: Include scalene muscles, sternocleidomastoid, and pectoralis muscles, which assist in deep or labored breathing. Accessory muscles are not typically used during routine breathing. However, in individuals with breathing difficulties, such as those with COPD, asthma, or heart failure, these muscles are engaged to assist with breathing. 1/22/2024 (C) KFU AY 24 -25 23 Muscles of Thoracic Wall; Lab. Work Three structures pass through and are protected by the costal groove in the upper rib within the intercostal space, collectively referred to as VAN: Vein, Artery, and Nerve (arranged from above downwards). Additionally, there is a collateral branch, which descends along the upper border of the lower rib and travels as a small bundle. 24 All the content of this slide is “from the reader.” The true muscles of the thoracic wall are the serratus posterior, levatores costarum, intercostal, subcostal, and transversus thoracis. The serratus posterior muscles and the levatores costarum muscles have a proprioceptive function (a source of chronic pain). Serratus Posterior Muscles Levatores Costarum Muscles All the content of this slide is “from the reader.” ((The intercostal muscles occupy the intercostal spaces)) The external intercostal muscles The external intercostal muscles (11 pairs) occupy the intercostal spaces from the tubercles of the ribs posteriorly to the costochondral junctions anteriorly. Anteriorly, the muscle fibers are replaced by the external intercostal membranes. These muscles run inferoanteriorly from the rib above to the rib below. The external intercostals are most active during inspiration. All the content of this slide is “from the reader.” The internal intercostal muscles The internal intercostal muscles (11 pairs) run deep to and at right angles to the external intercostals. Their fibers run inferoposteriorly from the floors of the costal grooves to the superior borders of the ribs inferior to them. Between the ribs posteriorly, medial to the angles, the internal intercostals are replaced by the internal intercostal membranes. The internal intercostals—weaker than the external intercostal muscles—are most active during expiration. All the content of this slide is “from the reader.” The innermost intercostal muscles The innermost intercostal muscles are similar to the internal intercostals and are essentially their deeper parts.Their actions are the same as those of the internal intercostal muscles. The fibers run in the same direction as the internal intercostal muscles (inferoposteriorly). All the content of this slide is “from the reader.” The subcostal muscles The subcostal muscles are thin muscular slips extend from the internal surface of the angle of one rib to the internal surface of the second or third rib inferior to it. All the content of this slide is “from the reader.” The transversus thoracis muscles The transversus thoracis muscles consist of four or five slips that radiate superolaterally from the posterior aspect of the inferior sternum. All the content of this slide is “from the reader.” Accessory Respiratory Muscles The axioappendicular muscles including the pectoralis major and pectoralis minor and the inferior part of the serratus anterior, may also function as accessory muscles of respiration, helping elevate the ribs to expand the thoracic cavity when inspiration is deep and forceful. The scalene muscles of the neck, also serve as accessory respiratory muscles by fixing these ribs and enabling the muscles connecting the ribs below to be more effective in elevating the lower ribs during forced inspiration. Accessory muscles of respiration- Lab. work 1/22/2024 (C) KFU AY 24 -25 25 Fascia of Thoracic Wall Deep fascia overlying the anterior The thoracic cage is lined internally with thoracic wall is called endothoracic fascia, over the apices of pectoral fascia (forms a major part of the bed of the breast) the lungs as the suprapleural membrane. ▪ Attached to the clavicle and sternum ▪ Invests the pectoralis major (C) KFU AY 24 -25 26 “From The Reader” Fascia of Thoracic Wall Pectoral fascia The clavipectoral fascia The endothoracic fascia Itis a thin, fibroareolar layer between the Deep fascia overlying It lies deep to the pectoral internal aspect of the thoracic cage and the the anterior thoracic fascia and is suspended lining of the pulmonary cavities, which can be wall (forms a major from the clavicle. It invests opened surgically to gain access to intrathoracic part of the bed of (encloses) the pectoralis structures. the breast) minor muscle. The lungs are composed of soft tissue, and if they come into direct contact with the ribs, they can be damaged. Therefore, they are covered by the pleura, but the pleura itself is delicate. To provide additional protection, there is the endothoracic fascia, a connective tissue layer that lines the entire thoracic cage and makes the walls smooth. This fascia becomes thicker at the borders of the first rib, forming the suprapleural membrane. This membrane is tight and prevents the apices of the lungs from extending into the neck. If the lung apices were to move into the neck, they could compress important blood vessels, such as the common carotid arteries, which supply blood to the brain. We have fascia covering the entire muscular system, grouping muscles together. Each individual muscle has its own fascia, and in the thorax, the fascia is named after the corresponding muscle. For example, the pectoralis muscle is covered by the pectoral fascia. There was a Quiz in theis lecture Pump Handle movement: Increase in.................dimension. Contraction of diaphragm during inspiration:increases...............Diameter. Bucket Handle movement: Increase in.................dimension. Answers in slides 34,35 This will be studied in detail in the Anatomy of the Heart lecture. Vessels of Thoracic Wall Subclavian Artery: Supplies blood to the upper limb and chest. Internal Thoracic Artery: Branches from the subclavian, supplies the anterior chest wall. Aorta: The descending aorta provides blood to the thoracic viscera. Intercostal Vessels: Run in the intercostal spaces, supplying the muscles, skin, and pleura. Origin of Posterior intercostals arteries from aorta. Origin of Anterior intercostals arteries from internal thoracic artery. Each Intercostal space supplied by one posterior and two anterior intercostal arteries. 1/22/2024 (C) KFU AY 24 -25 27 This will be studied in detail in the Anatomy of the Heart lecture. Vessels of Thoracic Wall ▪ Superior and Inferior Vena Cava: Major veins draining the upper body into the heart. ▪ Posterior intercostals veins end in Azygos veinous system. ▪ Anterior intercostals veins thoracic end in internal veins. 1/22/2024 (C) KFU AY 24 -25 28 “From The Reader” Nerves of Thoracic Wall As a doctor, you must know these things. Intercostal Nerves: Arising from the spinal nerves (T1- T11), they provide motor innervation to the intercostal muscles and sensory innervation to the skin and pleura. The anterior ramus of nerve T12, is the subcostal nerve Phrenic Nerve: Originates from the cervical spine (C3- C5), innervates the diaphragm. Vagus Nerve: Involved in autonomic control of thoracic organs, including the heart and lungs. The spinal nerves are divided into the anterior ramus and the posterior ramus. The posterior ramus goes to the back side and C3-C5 are the spinal segments that give The vagus nerve is a cranial nerve supplies all the structures of the back. rise to the right and left phrenic nerves. (X) and is the longest cranial nerve, These nerves descend through the neck running from the cranium and In Block 1.4, we will study that: and pass through the superior thoracic supplying the head, neck, thorax, 1. The cervical nerves combine to form the brachial plexus. aperture to enter the thorax. They supply trunk, and abdomen. It is part of the 2. The lumbar nerves combine to form the lumbar plexus. the diaphragm. Additionally, the phrenic autonomic parasympathetic system, 3. However, the thoracic nerves do not combine. Instead, they nerves provide some peripheral fibers to providing important functions by individually (directly) travel along the intercostal spaces and supply the lower place of the intercostal innervating the heart, blood vessels, form the intercostal nerves, which supply the thoracic wall spaces (NOT SURE). and lungs. (muscles, skin, etc.). “From The Reader” Nerves of Thoracic Wall The anterior The anterior rami of nerves T1-T11 ramus of nerve The posterior rami T12 The posterior rami of thoracic spinal The anterior rami of nerves T1-T11 The anterior ramus nerves pass posteriorly, immediately form the intercostal nerves of nerve T12, lateral to the articular Intercostal nerve supply: intercostal coursing inferior to processes of the vertebrae, to supply muscles and skin of thorax, (lower the 12th rib, is the the joints, deep back muscles, and intercostals nerves also supply muscles subcostal nerve skin of the back in the of abdomen and skin of abdomen. thoracic region. Nerves of Thoracic Wall The sympathetic trunk is a chain located in front of the necks of the ribs. From this chain, sympathetic fibers emerge and participate in forming the pulmonary plexuses, cardiac plexus, and other plexuses that supply various 1/22/2024 under sympathetic control. structures (C) KFU AY 24 -25 30 Knowledge of Intercostal space and structures is important for insertion of chest tube for drainage of blood, pus or fluid from thorax. Relation of vessel and nerve from above downwards (VAN): Intercostal Vein Intercostal Artery Intercostal Nerve 1/22/2024 (C) KFU AY 24 -25 31 Respiratory Tract It stats from the nose (nasal cavity -> pharynx -> larynx -> trachea -> primary bronchi (left & right) -> the lung 1/22/2024 (C) KFU AY 24 -25 32 Tracheobronchial Tree Larynx: (made of cartilages Thyroid, cricoid) Trachea: 10-12 cm long ▪ Tracheal rings of “C” shaped cartilages, keep trachea patent, prevent its collapse and allow expansion of esophagus during swallowing ▪ ends at the level of the sternal angle by dividing into the right and left main bronchi. Tracheabronchial tree starts from the larynx and end the trachea is made of cartilages so it has a firm up with the primary bronchi (left & right) feeling 1/22/2024 (C) KFU AY 24 -25 33 Main Bronchus (right & Left) Right main bronchus (Primary): in line with trachea (Hence foreign bodies commonly enter to right side), divides into three lobar (secondary) bronchi Left bronchus (Primary): left more horizontal, bronchus divides into two lobar (secondary) bronchi Carina the most sensitive area of the trachea for triggering the cough reflex, and can be seen on bronchoscopy 1/22/2024 (C) KFU AY 24 -25 34 Outside the alveoli lies a network of connective tissue and Trachea capillaries that play critical roles in supporting the alveoli and facilitating gas exchange. Primary bronchi (left & right) It is easier for foreign bodies Secondary bronchi (lobar bronchi) Right Left to enter the right bronchus Bronchi bronchi due to: 1- Wider Tertiary bronchi (Segmental Bronchi) 2- Shorter Shorter Longer 3-More in line with trachea Terminal bronchioles Wider Narrower Respiratory bronchioles More in line Alveolar ducts More horizontal with trachea Alveolar sacs divides into 3 divides into 2 lobes lobes Alveoli Tracheobronchial Tree 1/22/2024 (C) KFU AY 24 -25 35 Tracheobronchial Tree (Lab. Work) The trachea: Sensory innervation: Recurrent laryngeal nerve Arterial supply: Tracheal branches of the inferior thyroid artery Venous drainage: Brachiocephalic, azygos and accessory hemiazygos 1/22/2024 (C) KFU AY 24 -25 36 Cervical Trachea (Upper Part): Tracheal branches Arterial supply heart Aorta Subclavian Artery Thyrocervical Trunk Inferior Thyroid Artery Cervical Trachea (Lower Part): heart Aorta Bronchial Arteries Tracheal branches Cervical Trachea (Upper Part): Tracheal Inferior Thyroid viens Brachiocephalic viens Superior vena cava Venous drainage viens Cervical Trachea (Upper Part): Tracheal Azygos vein (right side) / Accessory hemiazygos vein Bronchial veins viens (left side) Superior vena cava innervation vags nerve Recurrent laryngeal nerve trachea and bronchi Pulmonary lymph nodes Bronchopulmonary lymph nodes Lymphatic Drainage Superior tracheobronchial lymph nodes Inferior tracheobronchial lymph nodes Paratracheal lymph nodes Bronchomediastinal lymph trunks Thoracic duct (left side) or Right lymphatic duct (right side) Tracheobronchial Tree (Lab. Work) Brochoscopy: A medical procedure that uses a bronchoscope (a flexible or rigid tube with a camera and light) to visualize the trachea, bronchi, and lungs. Also to take biopsy. 1/22/2024 (C) KFU AY 24 -25 37 “From The Reader” Right main bronchus: in line with trachea (Hence foreign bodies commonly enter to right side), wider, shorter, divides in to three lobar bronchi. Left main bronchus: more horizontal, narrow, longer, left bronchus divides into two lobar bronchi. Primary main bronchus (right & left) ↓ Secondary lobar bronchus (Three on right & two on left) ↓ Tertiary segmental bronchi (10 in right & 8 – 10 in left) ↓ 20-25 generations of conducting bronchioles ending as Terminal bronchioles ↓ Several generations of Respiratory bronchioles (transportation & gas exchange) ↓ 2 – 11 Alveolar ducts ↓ 5 – 6 Alveolar sacs ↓ Alveoli Lungs The differences between left & right lung is in the next slide which is from the reader 1/22/2024 (C) KFU AY 24 -25 38 “From The Reader” Right lung Left lung Two lobes (superior & inferior), Three lobes (superior, middle, one fissure (oblique), inferior), presence of cardiac notch on anterior two fissures (oblique and horizontal) , border, larger, heavier, shorter, wider, and presence of lingual at superior anterior border straight, lobe, groove for esophagus and cardiac cardiac impression on mediastinal impression on mediastinal surface, surface is much larger, absence of cardiac notch and groove for arch of aorta, absence of lingua, decending aorta, deeper concavity in inferior surface and a smaller groove for esophagus Lungs 1/22/2024 (C) KFU AY 24 -25 39 Lungs Right lung : Three lobe, two fissure, “From The Reader” In living light , soft, spongy and fully occupy the pulmonary absence of cardiac notch and cavities. absence of lingua. Apex (blunt superiorly above 1st rib) Base (resting on dome of diaphragm) Two /three lobes by one or two fissures Left lung: Two lobes, one fissure, Three surfaces (costal, mediastinal, diaphragmatic) presence of cardiac notch and Three borders (anterior, posterior, inferior) presence of lingula. (1) Always when there is an apex (pyramidal shape) there is a base (the base is over the diaphragm) (2) Anterior border (sharp) on the left side there is a cardiac notch (3) The medial site will be the costal surface, on the medial there is (the heart) 1/22/2024 (C) KFU AY 24 -25 40 Hilum: Passage for structures to and from lungs. Contents : 1.One pulmonary artery 2.Two pulmonary veins 3.Bronchus (two in right and one on left side) identified by firm cartilage in the wall 4.Bronchial vessels 5.Bronchopulomnary lymph nodes The concept of helium is the entry region where structures go inside the organ or outside. The entry (go inside): bronchi, pulmonary arteries, the nerves (go out): pulmonary vein, lymphatics The contents of the hilum of the lungs: one pulmonary artery two pulmonary veins from both sides, the bronchus, broncho-vessels that supply all the lung ( nutration supply), pulmonary supply (oxygenation- deoxygenation) ,lymph drainage 1/22/2024 (C) KFU AY 24 -25 41 “From The Reader” The hilum of the lung: A wedge-shaped area on the mediastinal surface of each lung through which the structures forming the root of the lung pass to enter or exit the lung. Roots of the lungs: The lungs are attached to the mediastinum by the roots of the lungs—that is, the bronchi (and associated bronchial vessels), pulmonary arteries, superior and inferior pulmonary veins, the pulmonary plexuses of nerves (sympathetic, parasympathetic, and visceral afferent fibers), and lymphatic vessels. The general arrangement is: Pulmonary artery: superiormost on left (the superior lobar or “eparterial” bronchus may be superiormost on the right). Superior and inferior pulmonary veins: anteriormost and inferiormost, respectively. Main bronchus: against and approximately in the middle of the posterior boundary, with the bronchial vessels coursing on its outer surface (usually on posterior aspect at this point). Pulmonary Lobule A pulmonary lobule is a subdivision formed as the bronchi branch into bronchioles. Functional unit of the lung Composed of upto 30 acini, supplied by distal pulmonary artery and bronchiole with multiple branches. Three components; lobular parenchyma, interlobular septal structure, centrilobular structure. Pulmonary lobule: Supplied by a single pulmonary artery and then veins (for each). Therefore, the pulmonary segments (it has separated septa) Supplied by single bronchus and it has their own arteries and veins. Because of that, we can remove it easily in case of fibrosis or malignancy. 42 Pulmonary Lobule In case of asthma: the smooth muscle contracts, causing the narrowing. Also, the secretion will be more, the mucus accumulated in the sinuses of the Alveoli 1/22/2024 (C) KFU AY 24 -25 43 Pleura ▪ It is serous covering of lungs. ▪ Outer layer: Parietal Pleura related to chest wall ▪ Inner layer: Visceral Pleura related to lungs Pleural Cavity: Cavity between parietal and visceral pleura containing small quantity of fluid. The pleura is connective tissue around the lungs it has two layers (visceral layer – partial layer) Between these two layers, there is a cavity filled with fluid called the pleural cavity In normal conditions, the fluid is low, while it goes high in a situation like a rib fracture. This causes damage, which leads to leaking air and blood (hemopneumothorax) (hemothorax, when there is only blood) (pneumothorax, when there is only air). However, because of injury like trauma, they usually leak together. 1/22/2024 (C) KFU AY 24 -25 44 Pleura Note: not all lobes are connected 100%. the pleura (the connective tissue) can go through between the lobes making (the fissure) and separating the lobes. Functions of the Pleura: 1-Lubrication: Pleural fluid in the pleural cavity reduces friction between the visceral and parietal pleura during breathing movements. Ensures smooth expansion and contraction of the lungs. 2- Maintaining Negative Pressure: The pleural cavity maintains a negative pressure (intrapleural pressure), which is lower than atmospheric pressure. 3-Facilitates Breathing 1/22/2024 (C)4-KFU AY 24 -25 Protection 45 Parietal Pleura 1- Cervical: associated with cervical bone 2- Costal: associated with chest wall (ribs and muscles) 3- Mediastinal: associated with the heart 4- Diaphragmatic: associated with the diaphragm 1/22/2024 (C) KFU AY 24 -25 46 “From The Reader” Each lung is invested by and enclosed in a serous pleural sac, consists of two continuous membranes: The visceral pleura: invests all surfaces of the lungs forming shiny outer surface The parietal pleura: lines the pulmonary cavities Pleural Cavity: potential space between parietal and visceral pleura containing small quantity of fluid for lubrication and allow smooth sliding during respiration. The lung expands and fills with air when the thorax expands while still allowing sliding to occur, much like a film of water between two glass plates. Visceral pleura is continuous with the parietal pleura at the hilum of the lung. Parietal pleura (costal, mediastinal, diaphragmatic and the cervical pleura) is thicker than the visceral pleura. The costal part of the parietal pleura is separated from the internal surface of the thoracic wall by: endothoracic fascia ( thin, extrapleural layer of loose connective tissue). Pneumothorax: Collection of air in pleural cavity. Pleural Effusion: Collection of fluid in this space. Lines of pleural reflection: Three lines of pleural reflection outline the extent of the pulmonary cavities on each side: 1. Sternal 2. Costal 3. Diaphragmatic “From The Reader” Sternal line of pleural reflection: Deviation of the heart to the left side primarily affects the right and left sternal lines of pleural reflection. From cervical pleura 2 -3 cm above the middle 1/3 of clavicle runs inferomedially , posterior to the sternoclavicular joints to meet at AML at the level of sternal angle. On right side continues to pass inferiorly in the AML to the posterior aspect of the xiphoid process (level of the 6th costal cartilage), where it turns laterally. On left side descends in the AML only to the level of the 4th costal cartilage. Here it passes to the left margin of the sternum and continues inferiorly to the 6th costal cartilage, creating a shallow notch as it runs lateral to an area of direct contact between the pericardium (heart sac) and the anterior thoracic wall. This shallow notch in the pleural sac, and the “bare area” of pericardial contact with the anterior wall, are important for pericardiocentesis. The costal lines of pleural reflection: Sharp continuations of the sternal lines The right costal line proceeds laterally from the AML. The left costal line begins at the MCL (midclavicular line). Both lines are symmetrical as they proceed laterally, posteriorly, and then medially, passing obliquely across the 8th rib in the midclavicular line (MCL) and the 10th rib in the midaxillary line (MAL), becoming continuous posteriorly with the vertebral lines at the necks of the 12th ribs. “From The Reader” The vertebral lines of pleural reflection: Much rounder, parallel the vertebral column, running in the paravertebral planes from vertebral level T1 through T12, posteriorly where continues with the costal lines. The lungs do not fully occupy the pulmonary cavities during expiration; thus the peripheral diaphragmatic pleura is in contact with the lowermost parts of the costal pleura, a potential pleural spaces here as the costodiaphragmatic recesses. The costal pleura is in contact with the mediastinal pleura, a potential pleural spaces here as the costomediastinal recesses. The inferior borders of the lungs move farther into the pleural recesses during deep inspiration and retreat from them during expiration. “From The Reader” The cervical pleurae and apices of the lungs pass into the supraclavicular fossae. The anterior borders of the lungs lie adjacent to the anterior line of reflection of the parietal pleura between the 2nd and 4th costal cartilages. On the right side, the pleural reflection continues inferiorly from the 4th to the 6th costal cartilage, paralleled closely by the anterior border of the right lung. The left pleural reflection moves laterally and then inferiorly at the cardiac notch to reach the 6th costal cartilage. The anterior border of the left lung is more deeply indented by its cardiac notch. Both pleural reflections and anterior lung borders pass laterally at the 6th costal cartilages. The pleural reflections reach the midclavicular line (MCL) at the level of the 8th costal cartilage, the 10th rib at the midaxillary line (MAL), and the 12th rib at the scapular line (SL). The inferior margins of the lungs reach the MCL at the level of the 6th rib, the MAL at the 8th rib, and the SL at the 10th rib, proceeding toward the spinous process of T10 vertebra. They then proceed toward the spinous process of T12 vertebra. “From The Reader” The parietal pleura generally extends approximately two ribs inferior to the lung. The oblique fissure of the lungs extends from the level of the spinous process of T2 vertebra posteriorly to the 6th costal cartilage anteriorly. The horizontal fissure of the right lung extends from the oblique fissure along the 4th rib and costal cartilage anteriorly. Pleura It lubricates the surfaces of the pleurae, allowing them to slide over each other. The serous fluid also produces a surface tension, pulling the parietal and visceral pleura together. This ensures that when the thorax expands, the lung also expands, filling with air. also create a division between major organs that prevents interference due to the movement of the organs, while preventing the spread of infection. Clinical: Collection of air in pleural cavity is known as Pneumothorax. Collection of fluid in this space is Pleural Effusion 1/22/2024 (C) KFU AY 24 -25 47 Pleura 1/22/2024 (C) KFU AY 24 -25 48 The Pulmonary Vasculature Each lung has a pulmonary artery supplying blood to it and two pulmonary veins draining blood from it (for oxygenation). Veins from the visceral pleura and the bronchial venous circulation drain into the pulmonary veins Veins from the parietal pleura join systemic veins of the thoracic wall. Always keep in mind that the lung it is different, the artery carries (deoxygenated blood) while the vein carries (oxygenated blood) 1/22/2024 (C) KFU AY 24 -25 49 Blood Supply of the Lungs Thepulmonary artery arises from the pulmonary trunk and carries deoxygenated, arterial blood to the alveoli. The pulmonary artery branches multiple times as it follows the bronchi One arteriole and an accompanying venule supply and drain one pulmonary lobule. Near the alveoli, the pulmonary arteries become the pulmonary capillary network. Where gas exchange occurs 1/22/2024 (C) KFU AY 24 -25 50 Blood Supply of the Lungs The pulmonary capillary network consists of tiny vessels with very thin walls that lack smooth muscle fibers. The capillaries branch and follow the bronchioles and structure of the alveoli. It is at this point that the capillary wall meets the alveolar wall, creating the respiratory membrane. Once the blood is oxygenated, it drains from the alveoli by way of multiple pulmonary veins, which exit the lungs through the hilum. 1/22/2024 (C) KFU AY 24 -25 51 Bronchial Vasculature ▪ Blood for nutrition of the structures making up the root of the lungs, the supporting tissues of the lungs, and the visceral pleura ▪ Distal branches anastomose the with branches of pulmonary arteries in the walls of the bronchioles and in the visceral pleura. ▪ The parietal pleura is supplied by the arteries that supply the thoracic wall. The thoracic aorta supplies the blood to the bronchial arteries witch supply the lung. 1/22/2024 (C) KFU AY 24 -25 52 Bronchial Vasculature ▪ The right bronchial vein drains into the azygos vein. ▪ The left bronchial vein drains into the accessory hemiazygos vein or the left superior intercostal vein. 1/22/2024 (C) KFU AY 24 -25 53 Pulmonary Vasculature 1. Pulmonary Arteries: 2. Pulmonary Capillaries: Right ventricle → Pulmonary trunk → Pulmonary arteries → Arterioles → Capillaries Right pulmonary artery → Supplies the right lung. surrounding alveoli. Left pulmonary artery → Supplies the left lung. Function: Gas exchange occurs here: 1-Oxygen diffuses into the blood. Function: Carry deoxygenated blood from the heart to 2-Carbon dioxide diffuses out into the alveoli. the lungs. 4. Bronchial Circulation (Separate System for Lung Tissue): 3. Pulmonary Veins: Arteries: Capillaries → Venules → Bronchial arteries (from aorta or intercostal arteries) → Two pulmonary veins from each lung (4 total). Supply the bronchi and non-alveolar lung tissue. Right and left pulmonary veins → Drain into the left Veins: atrium of the heart. Bronchial veins → Drain into the azygos vein (right) Function: Carry oxygenated blood back to the heart. and hemiazygos vein (left). Some bronchial venous blood drains into the pulmonary veins (a physiological shunt). Arterial supply of the lungs Pulmonary Three lobar segmental Left lung arteries arteries arteries Right pulmonary capillary arterioles artery networks Right pulmonary ventricle trunk Left pulmonary capillary arterioles artery networks RiPulmonary Two lobar segmental Left lung arteries arteries arteries Venous Return from the Lungs Venous Return is Corresponding to the arteries NOTE: the end will be the left atrium of the heart Arterial supply of the lungs Venous Return from the Lungs Lymphatic Drainage of the lungs Lung tissue and visceral Superficial (subpleural) Bronchopulmonary Pulmonary lymph nodes pleura lymphatic plexus. (hilar) lymph nodes Bronchomediastinal lymph Paratracheal lymph Superior tracheobronchial Inferior tracheobronchial trunks nodes lymph nodes (carinal) lymph nodes Thoracic duct (left and right Venous circulation (junction of internal side) jugular and subclavian veins). Lymphatic Drainage of the lungs innervation of the lungs Parasympathetic Innervation: Vagus nerve (CN X -10th cranial nerve-) → Pulmonary plexus → Bronchoconstriction Increased mucus secretion Minor vasodilation Sympathetic Innervation: Sympathetic trunk (T1–T5) → Pulmonary plexus → Bronchodilation Decreased mucus secretion Vasoconstriction Vagus nerve (CN X) → Cough reflex Stretch receptor signals (e.g., during breathing). Sympathetic fibers (via spinal nerves) → Pain sensation (nociception) from the lungs and pleura. innervation of the lungs “From The Reader” The Pulmonary Vasculature (For Oxygenation): Each lung has a pulmonary artery supplying blood to it and two pulmonary veins draining blood from it. Veins from the visceral pleura and the bronchial venous circulation drain into the pulmonary veins. Veins from the parietal pleura join systemic veins of the thoracic wall. Bronchial Vasculature(For Nutrition of the Structure): Bronchial arteries supply the root of the lungs, the supporting tissues of the lungs, and the visceral pleura. The two left bronchial arteries usually arise directly from the thoracic aorta. The single right bronchial artery may also arise directly from the aorta. Most commonly arises indirectly from upper posterior intercostal arteries (usually the right 3rd posterior intercostal artery), or from a common trunk with the left superior bronchial artery. The right bronchial vein drains into the azygos vein. The left bronchial vein drains into the accessory hemiazygos vein or the left superior intercostal vein. The superficial (subpleural) lymphatic plexus lies deep to the visceral pleura and drains the lung parenchyma (tissue) and visceral pleura, finally drain into the bronchopulmonary lymph nodes (hilar lymph nodes) in the region of the lung hilum. “From The Reader” The deep lymphatic plexus is located in the submucosa of the bronchi and in the peribronchial connective tissue, draining structures in root of the lung → into the intrinsic pulmonary lymph nodes along the lobar bronchi → into the bronchopulmonary lymph nodes → to the superior and inferior tracheobronchial lymph nodes → to the right and left bronchomediastinal lymph trunks → terminate on each side at the venous angles (junctions of the subclavian and internal jugular veins). The right bronchomediastinal trunk converges here to form the short right lymphatic duct. The left bronchomediastinal trunk terminates in the thoracic duct. Lymph from the parietal pleura drains into the lymph nodes of the thoracic wall (intercostal, parasternal, mediastinal, and phrenic) and from the cervical parietal pleura drain into the axillary lymph nodes. Lymphatic Drainage 1/22/2024 (C) KFU AY 24 -25 54 Nervous Innervation of the Lungs Reflexes such as coughing, and the ability of the lungs to regulate oxygen and carbon dioxide levels, also result from this autonomic nervous system control. Sensory nerve fibers arise from the vagus nerve, and from the second to fifth thoracic ganglia. Thepulmonary plexusis a region on the lung root formed by the entrance of the nerves at the hilum. Presynaptic fibers from vagus synapse with nerve, parasympathetic ganglia in pulmonary plexus. The nerves then follow the bronchi in the lungs and branch to innervate muscle fibers (bronchoconstrictor), glands (secretomotor) , and blood vessels (vasodilator). 1/22/2024 (C) KFU AY 24 -25 55 Nervous Innervation of the Lungs Sympathetic fibers (postganglionic) from paravertebral sympathetic ganglia of sympathetic trunk. Sympathetic fibers are inhibitory Bronchial (bronchodilator), motor to pulmonary muscle vessels (vasoconstrictor) and inhibitory to alveolar glands (type II secretory cells). 1/22/2024 (C) KFU AY 24 -25 56 Nervous Innervation of the Lungs Visceral afferent fibers of plexus: Reflexive: (cell bodies in sensory ganglia of vagus nerve) nerve endings associated with cough reflex, stretch reception, Hering breuer reflex, receptors sensitive to BP Pulmonary arteries, sensitive to blood gas levels pulmonary veins Nociceptive: accompany sympathetic fibers from visceral pleura and bronchi, from trachea accompany vagus nerve. Pain impulse generated in response to Painful/injured stimuli: Chemical irritants Ischemia Excessive stretch 1/22/2024 (C) KFU AY 24 -25 57 Nervous Innervation of the Lungs Visceral pleura by pulmonary plexuses The nerves of parietal pleura: intercostal and phrenic nerve Costal and diaphragmatic part periphery by intercostal nerve Central and mediastinal part by phrenic nerve. Mediate sensation of touch and pain. 1/22/2024 (C) KFU AY 24 -25 58 “The eye sees only what the mind is prepared to comprehend.” Robertson Davies 1/22/2024 (C) KFU AY 24 -25 59 Chest x ray Identify the Clinical Findings Features consistent with right middle and/or lower normal lobe consolidation, most likely due to pneumonia. The costophrenic recess is a potential space in the pleural cavity located at the junction of the costal pleura (lining the inner surface of the ribs) and the diaphragmatic pleura (covering the diaphragm). It allows the lungs to expand during deep inspiration. 1/22/2024 (C) KFU AY 24 -25 60 There was a Quiz in theis lecture The right lung has three lobes and two fissures. The left lung has two lobes and one fissure. It has special characteristics, including the cardiac notch and the lingula. Summary 1. The major components of the thoracic wall, include ribs, thoracic vertebrae and sternum as skeleton with superior and inferior apertures, intercostal muscles, vessels and nerves are part of intercostal spaces. 2. The surface features of thoracic wall, include vertical lines (AML, PML, MCL, VL, Axillary lines ) used as a reference points for the underlying structures. 3. There are differences between the right and left side of bronchial tree, lungs and pulmonary and bronchial vasculatures of lungs. 4. The movements of diaphragm and thoracic wall muscles are responsible for thoracic cavity changes during inspiration and expiration, and ‘normal’ and forced respiration. 1/22/2024 (C) KFU AY 24 -25 61 REFERENCES: Clinically Oriented Anatomy (8th ed.) 1/22/2024 (C) KFU AY 24 -25 62 1/22/2024 (C) KFU AY 24 -25 63